The focus of discussions in Thailand and Japan will be on building improved trade relations, building on the Conservative government's recent mission to China.

Prime Minister Stephen Harper is welcomed by General Yuthasak Sasipropha, deputy Prime Minister of Thailand, as he arrives in Bangkok, Thailand on Thursday. (Sean Kilpatrick/Canadian Press)

But the trip will be capped off early next week with a meeting in South Korea where leaders from 53 nations will discuss nuclear security and how to keep weapons of mass destruction out of the hands of terrorists.

While not officially on the agenda, the nuclear programs of both North Korea and Iran are expected to be discussed.

The talks in Seoul have drawn repeated threats from Pyongyang, which has gone from describing the summit as a "severe provocation" to declaring on Wednesday that any condemnation of its nuclear program would be tantamount to "a declaration of war."

The reclusive regime has rarely backed up its threats.

Trade talks to begin

It is widely expected that Harper will announce Friday exploratory talks with Thailand on his first official visit to see if the two nations can reach a free trade deal.

An international trade expert says Thailand is an important stepping stone for Canada if it wants access to the Association of Southeast Asia Nations trading block.

"We would hope that the Philippines, Vietnam and Indonesia might follow soon," said Peter Clark, president of Grey, Clark, Shih and Associates, Ltd., one of Canada's most active trading companies.

"Thailand is an expanding economy. Opening the market to Canadian trade and investment will create opportunities for Canada to participate in supply chain links with China and Japan."

At the moment, two-way trade between Canada and the southeast Asian nation amounts to about $3.5 billion, much of it weighted towards the Thai electronics and machinery sectors.

It accounts for $2.7 billion of the total -- a figure that underscores the urgency as far as Clark is concerned.

"If we are not inside the tent our competitors will have a significant advantage and hopes of narrowing or eliminating the significant trade imbalance will be lost," he said.

Thai business leaders are eager to capture more Canadian energy exports, something that was underscored when the country's state-owned oil firm PTT Exploration and Production invested $2.3 billion in the Alberta oilsands project almost 18 months ago.

They also signalled that they are interested in striking a deal for Canadian natural gas.

Harper will meet with Thai Prime Minister Yingluck Shinawatra, who assumed her post in August of last year.

But the two-day visit is expected to be a warmup for the prime minister's stop in Japan, where he and Prime Minister Yoshihiko Noda are anticipated to formally launch free trade negotiations and as well as a relaxation of Japanese restrictions on imported Canadian beef.

The talks are significant because both countries were shut out of the recent Trans-Pacific Partnership talks.

The trading relationship between Japan and Canada amounts to almost $24 billion a year. Officials in Ottawa have signalled they'd like to see more Canadian export access to Japan's closely guarded agriculture, food and beverage, as well as aerospace and defence markets.

It is unclear how long it might take to strike a comprehensive free trade deal.

During his discussions, Harper will be joined by a phalanx of cabinet colleagues, including Foreign Affairs Minister John Baird, International Cooperation Minister Bev Oda and Trade Minister Ed Fast.